Add kernel/closed_world_test

pkg/compiler/lib/src/enqueue.dart

Index: pkg/compiler/lib/src/enqueue.dart
diff --git a/pkg/compiler/lib/src/enqueue.dart b/pkg/compiler/lib/src/enqueue.dart
index 75cf2f7368e429e4cc8c890c91b2e7196c2118ec..5da883162e80eced8b22c755a7f2bf99a642fc0c 100644
--- a/pkg/compiler/lib/src/enqueue.dart
+++ b/pkg/compiler/lib/src/enqueue.dart
@@ -217,7 +217,7 @@ class ResolutionEnqueuer extends Enqueuer {
       _universe.registerTypeInstantiation(type,
           isNative: isNative,
           byMirrors: mirrorUsage, onImplemented: (ClassElement cls) {
-            backend.registerImplementedClass(cls, this);
+        backend.registerImplementedClass(cls, this);
       });
       if (globalDependency && !mirrorUsage) {
         globalDependencies.registerDependency(type.element);